In schistosomiasis, the deposition of parasite ova within tissues is the initial event in a complex pathophysiological cascade which is characterized by granuloma formation and term- inates in hepatic fibrosis and related clinical sequela. We have developed an in vitro model of granuloma formation which has provided a vehicle to study granuloma formation and fibrosis and the regulation of these phenomena. These studies will analyze the cellular constituents of granulomatous hypersen-sitivity and their modes of interaction at the molecular level. To accomplish this goal four major approaches are anticipated: 1. The use of collagen matrix beads: These beads permit the in vitro development of a three-dimensional recapitulation of the in vivo granuloma and facilitate the evaluation of cellular constituents, interaction and the role of antigens, growth, chemotactic, and adherence factors in granuloma formation. 2. Assessment of the role of T regulatory factors: Evidence for the production and role of defined "T regulatory" factors such as interleukins, interferon, and growth factors will be sought. In addition, regulatory factors, bearing specific phenotypic determinants and an antigen receptor, have been produced from the T cells obtained from infected mice. These factors specifically inhibit in vitro and in vivo granuloma formation; when analyzed for structure and function the factors promise to be important regulatory molecules. 3. T cell cloning technology: We have previously reported T clones capable of inducing in vitro granuloma and, more recently, have developed technology to produce suppressor T clones. These T clones will be used to analyze specific interactions of the regulatory populations. In addition, they will be used to define immunogenic epitopes relevant toward granuloma formation or its regulation. 4. Application of molecular biological analysis: The ultimate goal of these studies is to understand the specific molecular signals for the development and modulation of granulomatous hypersensitivity for the production and activation of various T regulatory and molecules or pathways is anticipated using multiple modes of analyses including a Confocal microscope. This information will be applied to the long range goal of reducing morbidity in schistosomiasis by directed immunomodulation of granulomatous hypersensitivity.